How can add a light gray shadow to a UIButton, I don't want a method to do this at the moment, it should be something like:
UIButton *button1... button1.layer.shadowOpacity = 0.8
etc, but that doesn't work, it only adds a shadow inside the button, but I need it on the outside. Thanks!
First you have to #import <QuartzCore/QuartzCore.h>. Then:
mybtn.layer.shadowColor = [UIColor blackColor].CGColor;
mybtn.layer.shadowOpacity = 0.5;
mybtn.layer.shadowRadius = 2;
mybtn.layer.shadowOffset = CGSizeMake(3.0f,3.0f);
You can also use –[UIButton setBackgroundImage:forState:] to set the background image for UIControlStateNormal to one with a shadow. E.g.:
[button setBackgroundImage:[UIImage imageNamed:#"ButtonBackgroundNormal"]
forState:UIControlStateNormal];
where ButtonBackgroundNormal.png has a shadow. Images often render faster than drawing with code. And, speed is important, especially if you're adding it to a UITableViewCell. In that case, to speed up scrolling speed, make sure the background image is completely opaque by designing it with the same background color of the UITableViewCell and saving it without transparency. Then, set button.opaque = YES.
Related
I have created a screen tutorial for my app.
I've done this by creating a PageViewController to manage 4 viewControllers.
In the PageViewController I have implemented the following code
self.modalPresentationStyle = UIModalPresentationFormSheet;
I have also set the alpha on the pageViewController view to .45
This makes the PageViewController transparent which is exactly what I want.
However, it is also making everything inside the 4 viewControllers that are being managed by the PageViewController transparent i.e. buttons, labels, etc.
How can I stop all of those object from being transparent?
Views always work like this. If you wanted to make a view semi-transparent, it would usually be pretty vexing if that didn't also affect all of its subviews. The times when you want your alpha setting to also affect the subviews likely far outnumber the times when you don't.
What you can do instead of making the view transparent is to make its background color transparent. That is, instead of:
self.view.backgroundColor = [UIColor blueColor];
self.view.alpha = 0.45;
you can do:
self.view.backgroundColor = [UIColor colorWithRed:0 green:0 blue:1 alpha:.45];
That way, your subviews are not affected, because while the alpha of your main view's background color is 0.45, the alpha of the view itself is still 1.0.
To change the background color of a view, use the following on the view:
[viewController.view setBackgroundColor:[UIColor COLOR]];
where COLOR is the color you would like (i.e. whiteColor)
I'm working on some drawing code. I have that portion working great.
I want to draw over an image, but I want to still be able to see the detail of the image, the black lines, etc.
What I am working on is making a transparent UIImageView that holds the image.
I'm not sure how to get this set up properly though.
Should this be added above the other UIImageView that I color on or below it?
Here's what I have so far:
- (void)viewDidLoad
{
[super viewDidLoad];
topImageView = [[UIImageView alloc] initWithFrame:CGRectMake(0, 46, 320, 370)];
[topImageView setImage:[UIImage imageNamed:#"imagesmall.png"]];
topImageView.alpha = 1.0;
topImageView.layer.opacity = 1.0;
topImageView.layer.opaque = NO;
[self.view addSubview:topImageView];
[topImageView release];
}
Thoughts anyone?
Yes, you can draw views over other views. They are drawn in the order that they're added as subviews, unless you reorder them after that.
You may need to set the opaque property for some views (this is distinct from and overrides their layer opacity), and set their backgroundColor to nil. UIImageView seems to be transparent by default, as long as its image is; some other UIView subclasses are not.
So, just what is your overlay going to be? If you just need to display one image over another, what you have here seems to work already. If you need to draw some lines programmatically, you'll need to do this:
Create a subclass of UIView.
Implement its drawRect method to display the content you need.
When you add your custom view on top of the background image, make sure it is not opaque and has no backgroundColor.
A common problem here is to find that your foreground is working, but the background isn't being loaded properly. To make sure the background is there, set the alpha of the foreground view to 0.5. You won't want to do that in production, but it will allow you to verify that both views exist.
Is there any way to change the composite mode of a UIView background say to screen, overlay, or multiply?
The effect I am trying to go for is similar to what appears in the iOS notification centre where the cell background is much darker, however still translucent to the background. This looks to me like a multiply effect in photoshop.
I'm not 100% sure what your referring to but play around with the background colour and alpha
view.backgroundColor = [UIColor blackColor];
view.alpha = 0.4f; // Try changing this to suit
They may be using subtle gradients and other additional embellishments to really fine tune the look.
Update
I can get a fairly convincing reproduction using
backgroundColor = [UIColor colorWithWhite:0.0f alpha:0.37f];
whitePixelLine = [UIColor colorWithWhite:0.8f alpha:0.4f];
darkPixelLine = [UIColor colorWithWhite:0.0f alpha:0.6f];
My graphic skills are terrible so this could be way off the mark
I was wondering how I actually use background in normal tableview(non grouped). For example take a look at the clock app and the background there. Any ideas?
You can set the background of your table view using the same techniques as the grouped table view (something like self.tableView.backgroundView = anImageView;), but your cells' background are opaque and, therefore, will hide it.
You'll then have to set, in tableView:cellForRowAtIndexPath: the background color of your cells to clearColor [UIColor clearColor] and it's backgroundView to nil.
Run the app now, and there might still be something wrong: the background of the cell's labels is possibly also opaque (I say possibly because the cells might have picked up the cell background color and changed the background color of their subviews accordingly).
If it is the case, once again, in tableView:cellForRowAtIndexPath:, set the subviews's background color to clearColor.
You can also try to set image view with your own image as backgroundView:
UIImage *yourImage = ...
UIImageView *imageView = [[UIImageView alloc] initWithImage:yourImage];
self.tableView.backgroundView = imageView;
[imageView release];
So right now I have a UIView with a UILabel in it. I want the background to have an opacity < 1.0 and the label to have an opacity of 1.0. However since alphas propagate down the view hierarchy, the label ends up with an opacity < 1.0 as well.
Is there anyway to do what I want without making the UILabel a subview of another view??
Just set the background color to be semitransparent:
view.backgroundColor = [[UIColor blackColor] colorWithAlphaComponent:0.5f];
Or, in Swift:
view.backgroundColor = UIColor.blackColor().colorWithAlphaComponent(0.5)
Or, Swift 3:
view.backgroundColor = UIColor.black.withAlphaComponent(0.5)
Note that, in this particular case, UIColor(white: 0, alpha: 0.5) is more concise, but colorWithAlphaComponent will work in general.
Besides being available in code, you can do this quite easily from iB as well:
Within the storyboard, select the view you wish to edit;
From the right panel, make sure the Attributes inspector is opened;
Click on the right side of the "Background" drop down box and choose "Other ..."; it will open a colour picker dialog;
Change the "Opacity" at the bottom to set the background colour opacity.
You can set the background color of the UIView with a semi-transparent color or make the image itself semi-transparent. This way it's a property of the view that is transparent, not the view itself.
You can use this:
self.view.layer.opacity=0.5